1. Field of the Invention
The present invention relates to an impregnation composition which, when coated on the surface of cement concrete, serves to densify the concrete body surface and to prevent penetration of water or carbon dioxide into the interior. Further, it relates to a primer composition for resin concrete which, when resin concrete is coated on a cement concrete substrate surface, serves to improve the bond strength between the cement concrete substrate surface and the resin concrete. Particularly, it relates to a primer composition for resin concrete which serves to improve the bond strength with a cement concrete substrate in a wet condition.
In this invention, cement concrete means inorganic concrete or mortar.
2. Discussion of Background
Cement concrete is excellent in durability and is widely used in the field of civil engineering and construction, for example, for flooring of buildings or pavement of roads. However, cement concrete is susceptible to erosion by rain, wind, sewage, carbon dioxide and chemicals, and it is desirable to protect such cement concrete by impregnating or coating the cement concrete substrate surface with a resin composition. As a method for protecting cement concrete, a method of using an impregnation composition or a method of using resin concrete may be mentioned.
The method of using an impregnation composition is a method wherein an impregnation composition is impregnated to void spaces in cement concrete to impart resistance against erosion by water or carbon dioxide. The impregnation composition may, for example, be of an epoxy resin type or an acrylic resin type.
The method of using resin concrete may, for example, be a method wherein a cement concrete substrate surface is covered or coated with resin concrete to impart chemical resistance or wear resistance.
Use of resin concrete has been rapidly expanding in recent years by virtue of its characteristics such as excellent chemical resistance and high strength. Commonly used among such resin concretes are resin concretes of e.g. epoxy resin type, urethane resin type, unsaturated polyester resin type and acrylic resin type. These various resin concretes have various characteristics depending upon the natures of their main component resins.
Among these resin concretes, attention has been drawn to unsaturated polyester resin type and acrylic resin type radical polymerizable resin concretes, since their low temperature applicability is good.
However, conventional impregnation compositions have had problems such that they are hardly reactive at a normal temperature or have a high viscosity, so that they have to be subjected to heat polymerization, which makes the operation cumbersome.
As an impregnation composition useful at a normal temperature, an impregnation composition containing a monofunctional (meth)acrylate having a dicyclopentadiene structure in its molecule, has been proposed (JP-A-5-254960). However, this impregnation composition has had a problem that it is required to be impregnated under pressure, which makes the operation cumbersome.
On the other hand, the above mentioned conventional resin concretes also have a draw back that their bond strength is inadequate against a wet surface substrate such as cement concrete wet with water. Accordingly, there has been a problem that the cement concrete substrate surface has to be sufficiently dried prior to application of the resin concrete, which makes the operation cumbersome.
Further, a primer containing a monofunctional (meth)acrylate having a dicyclopentadiene structure in its molecule, has been proposed as a primer which, when coated on a cement concrete substrate surface, serves to improve the bond strength between the substrate surface and resin concrete (JP-A-4-224184). However, this primer has had problems that the bond strength is still inadequate between a wet substrate surface and resin concrete, and the cured product of the primer is brittle and poor in durability.